Hydrolyzable organic silane compounds chemically combine with glass, ceramics, wood, paper, fibers, resins and other various materials and are widely used as silane couplers in various industrial fields.
It has been attempted to introduce antibacterial groups into silane coupler compounds and to provide the surface of various materials with antibacterial activity utilizing chemical affinity of silane coupler compounds to various materials. By fixing antibacterial moieties of the compounds to the surface of various materials, the materials are provided with long lasting antibacterial activity free from danger of environmental pollution. This will reduce appearance of antibiotic-resistant strains and enable disinfection of a large amount of materials and continuous disinfection.
Silane compounds having a quaternary ammonium salt in their molecule as an antibacterial moiety were proposed (JP2-6489A). However, quaternary ammonium salt is an ionic compound and thus influenced by coexisting inorganic salts, sugars, proteins, etc. losing antibacterial activity or suffering discoloration. The active polar portion thereof is small in comparison with the alkyl chain in the molecule, and, therefore, when it is applied to the surface of fibers for instance, the fiber surface become water repellent because of introduction of the long chain alkyl group, that is, the fibers lose their inherent hygroscopic property. In the case of woven fabric, water or steam permeability and impregnation property thereof are impaired. Therefore, there has been a demand for a compound which can provide fibers with long-lasting excellent antibacterial activity without impairing inherent hydrophilicity of fibers.
Many and various antibacterial substances are known including quaternary ammonium compounds. Guanidyl compounds, which are known to have biological activity such as antimalarial, are examples of such compounds.
However, the mechanism of germicidal activity of these compounds is not yet quite clearly understood and presence of a specific group does not always cause germicidal activity. It is well known that biological activity of biguanide compounds remarkably varies depending on the species of substituents. (Refer to: J. Chem. Soc., 729 (1946).
The object of the present invention is to provide compounds which will solve problems of antibacterial-activity-providing compounds and are able to provide a wide range of materials with long-lasting antibacterial activity.
We prepared a class of novel compounds, which comprise a hydrolyzable silane coupler compound at the molecular end of which a guanidyl group is attached and found that some of them have strong germicidal activity and are practically useful as antibacterial agents. These compounds have excellent hydrophilicity and have no ionic moiety and thus the above described problems are unexpectedly solved at one effort. Thus we completed this invention.